Wrist-watch casing

ABSTRACT

A wrist-watch casing comprises a casing body, a bezel, a blind bore formed in either of the casing body or the bezel, and a metal coil tightly wound and plated with fusing alloy. The metal coil is inserted into said bore and fusingly attached to the inner wall of the bore, and a threaded member screwed to the metal coil which forms the female thread, so that a casing back or the bezel can be rigidly connected to the casing body.

United States Patent 1191 Keida Oct. 7, 1975' [54] WRIST-WATCH CASING 3,729,924 5/1973 Aoki 58/90 R [75] Inventor: Teruho Keida, Tokorozawa, Japan FOREIGN PATENTS OR APPLICATIONS 209,195 3 1940 Switzerland 58/90 R [73] Asslgnee z g h 210,235 9/1940 Switzerland 58/90 R 2 p 305,774 5/1955 Switzerland 58/90 R 22 Filed; Aug, 1974 206,982 12/1939 Switzerland 58/90 R App]. No.2 498,366

Primary Examiner-George H. Miller, Jr. Attorney, Agent, or Firm-Ernest G Montague; Karl F. Ross; Herbert Dubno 8 Claims, 8 Drawing Figures US. Patent Oct. 7,1975 Sheet 1 of2 3,910,031

%uWp/Q US. Patent Oct. 7,1975 Sheet 2 of 2 3,910,031

WRIST-WATCH CASING The present invention relates to a wrist-watch casing assembled by means of screws which connect a casing back to a central casing body or a bezel to a casing body.

Recently, it has been attempted to improve the. character of a wrist watch casing under any conditions, which may cause rust and corrosion of the internal mechanism of the watch, but these attempts have not been successful with new materials giving various designs to the wrist watch casing. I

Thus, the prior art screw threaded connection could not be adopted in a wrist-watch casingassembly'made of such materials as stainless steel, cemented carbides and ceramics, because a threaded bore for screw insertion could not be formed in such material without its destruction.

Of course, in order to allow the partsof the wristwatch casing to be detachable, and adhesive could not be used.

An object of this invention is to provide a wrist watch casing which can have a threaded bore in a bezel or casing body, even if it is made of a material such as stainless steel, cemented carbide and ceramics, characterized by hard machinability.

This and other feature and advantages of this invention will be understood from the following description with reference to the accompanying drawing, in which:

FIG. 1 is a cross-sectional view of a blind bore and a metal coil to be inserted into said bore, according to an embodiment of this invention;

FIG. 2 is a cross-sectional view of a threaded bore formed by means of this invention, and a screw cooperating with this bore;

FIG. 3 is a cross sectional view of a screw threaded connection according to this invention;

FIG. 4 is a front view of a wrist-watch casing embodying the present invention;

FIG. 5 is a cross section of the watch casing taken along the line AA of FIG- 4.

than that of the bore 1 in order to avoid the deformation of the'thread-and incomplete brazing.

Into the threadedbore 1 may be detachably inserted a screw 5 which has a helical threaded portion with an arc rate cross-section (shown in FIGS. 2 and 3). The threadedportion may be provided. with a rhombic crosssection. In an embodiment of FIGS. 4 and 5, the wrist watch casing has'a bezel 2 with threaded bores l and a one-piece type casing'body 3 having through'going bores 6 through which-screws 5 arethreaded to; the bores 1 so that the bezel 2 is tightly connected to the casing body 3 to maintain a waterproof seal. A glass plate 7 is rigidly supported through a packing ring 8 to the front surface of the casing body 3 by pressure from the bezel 2 alongall'of the edges of the-glass plate 7.

In another embodiment of FIG. 6, the wrist-watch casing is separated to two pieces, a center casing body 9 and an inner body 12. I

The threaded bores l are formed in the center casing body 9, into which are inserted screws 5 each passing through a bore 11 formed at the peripheral portionof a casing back 10.

Accordingly, the inner body 12 is supported tightly to a bezel portion integrally formed with the center casing body 9 by the compression by casing back 10 of body 12 via a packing ring 13.

In still another embodiment shown in FIG. 7, a casing back 10 is integrally formed with an inner body 12 and separates from an attaching ring 14. Thus attaching ring 14 has through bores 15 through-going which screws 5 are passed to be threaded into threaded bores '6 formed in a center casing body 9, so that the casing back 10 is fixed to the center casing body 9 together with a glass plate 7 and a packing ring 8.

FIG. 8 depicts an embodiment of the wrist-watch cas- I ing of a screw-back type. In this embodiment, a casing back 10 is threaded to a large threaded bore 6 formed in the back portion of a center casing body 9. A screw 5 is integrally formed with the casing back 10, and the threaded bore 6 is produced by the coil device men- FIG. 6 is a cross section similar to FIG. 5 of another embodiment of this invention in which the watch casing is sectioned along a line similar to line AA in FIG. 4;

FIG. 7 is a cross section similar to FIG. 5 of a furtherembodiment of this invention in which the watch casing is sectioned along a line similar to line AA in FIG. 4;

and 1 FIG. 8 is a cross section similar to FIG. 5 of still ,another embodiment of this invention in which the watch casing is sectioned along a line similar to line AA in FIG. 4.

Referring to the drawings, a blind bore 1 is formed in a bezel 2 (shown in FIGS. 4 and'5) or a casing body 3 (shown in FIGS. 6 and 7). The bezel 2 or casing body 3 is made of stainless steel and the bore l-has a circular inner wall to be smooth. A metal coil 4, for example,

a stainless steel coil tightly wound (ie with successive turns in axial contact) is coated or plated with fusing alloy, for example, nickel phosphide. The'plated layer may have a thickness of approximately 10 microns.

Said plated coil 4 is tightly inserted into said bore 1 and heated at a temperature of about l, C in a nonoxiding' furnace so that'the alloy is fused'in the bore 1 thereby to bond the coil, as a threaded portion, in the bore 1. The diameter of the coil 4 may be slightly less tioned above.

The blind bore 1 may be coated with nickel before the insertion of the coil 4 in the case in which the blind bore 1 is formed by means of erosion, electro-beam, su-

personic vibration, laser beam, etc., in a bezel or casing body of such material as cemented carbide and ceramics, whereby the coil 4 is tightly attached to the peripherally of the bore 6 because the nickel coating has excellent affinity for the brazing. Silver is lized as a. coating material. p

What is claimed is: 1. A wrist-watch casing comprising: a casing-member, a bezel member and a back mem ber interconnected to'define a watch-casing strucsaid members-is made of stainless steel and said coil is composed of stainless steel coated with nickel phosphide fused to the wall of said bore.

the

preferably uti-.

3. The casing defined in claim 1 wherein said one of said members is composed of a material selected from the group which consists of cemented carbide or ceramic, said wall of said bore having a nickel coating fused to said coil.

4. The casing defined in claim 1 wherein a throughgoing bore is formed in said other member and said element is a screw traversing said throughgoing bore..

5. The casing defined in claim 1 wherein said element is a threaded projection formed unitarily on said other member.

6. The casing defined in claim 1 wherein said bore is formed in said bezel member, said casing member being provided with a throughgoing bore registering with said blind bore, said element being a screw tramember is a ring surrounding said casing member. 

1. A wrist-watch casing comprising: a casing member, a bezel member and a back member interconnected to define a watch-casing structure; a blind bore formed in one of said members; a helical metal coil of mutually adjoining turns of circular cross-section received in said bore and fused to the wall thereof to form a female thread; and a male threaded element threaded into and removable from said female thread to retain another of said members against said one of said members.
 2. The casing defined in claim 1 wherein said one of said members is made of stainless steel and said coil is composed of stainless steel coated with nickel phosphide fused to the wall of said bore.
 3. The casing defined in claim 1 wherein said one of said members is composed of a material selected from the group which consists of cemented carbide or ceramic, said wall of said bore having a nickel coating fused to said coil.
 4. The casing defined in claim 1 wherein a throughgoing bore is formed in said other member and said element is a screw traversing said throughgoing bore.
 5. The casing defined in claim 1 whereiN said element is a threaded projection formed unitarily on said other member.
 6. The casing defined in claim 1 wherein said bore is formed in said bezel member, said casing member being provided with a throughgoing bore registering with said blind bore, said element being a screw traversing said throughgoing bore, said bezel member clamping a glass plate and a sealing ring against said casing upon tightening of said screw.
 7. The casing defined in claim 1 wherein said blind bore is formed in said bezel, said back member having a throughgoing bore along with said blind bore, said element being a screw traversing said throughgoing bore and clamping said bezel member against said casing member and said back member, said casing further comprising a sealing ring interposed between at least two of said members.
 8. The casing defined in claim 7 wherein said pack member is a ring surrounding said casing member. 